Patterns of Age- and Sex-Related Variations in Bone Mineral Density of Lumbar Spine and Total Femur: A Retrospective Diagnostic Laboratory-Based Study

BACKGROUND: Osteoporosis is a major public health problem and should be a priority for healthcare providers and policymakers as it is an important reason of morbidity, mortality, and high-cost incurred in the management of its complications such as hip fractures. This study is designed to assess the bone mineral density (BMD) variation with age, site, and sex. Study is based on diagnostic laboratory data of BMD. METHODS: A retrospective analysis was conducted on a sample population of 935 persons (73.5% women, 26.4% men), who underwent dual-energy X-ray absorptiometry scan between 2015 and 2017 in a National Accreditation Board for Testing and Calibration Laboratories accredited Mumbai (Maharashtra, India) based diagnostic laboratory. Lumbar spine, right and left total femur, BMD were analyzed across age, sex, and sites. The prevalence of low BMD and osteoporosis at these sites has been estimated as per the World Health Organization criteria of osteoporosis diagnosis using T scores. RESULTS: Overall the prevalence of osteoporosis was found to be 6.4%, 5.5%, and 16.4%, while the prevalence of low BMD was 32.6%, 32.8%, and 31.2% at right total femur, left total femur, and lumbar spine, respectively. The decline in BMD at lumbar spine is more among women and it was a consistent decline with age, while among men' decline rate was less at all three sites. CONCLUSION: Our study highlighted the variation of BMD at different sites of body and higher vulnerability of spine for fragility fractures. Our study has shown a sharp decline in BMD among women during transition from 5(th) to 6(th) decade which signifies association of menopause with osteoporosis. Major limitation of the study is unavailability of clinical profiles of the subjects because of which it is difficult to ascertain whether BMD estimation was a diagnostic or screening procedure. In addition, study is conducted in diagnostic lab settings, due to which it is possible to overestimate prevalence of low BMD and osteoporosis by extrapolating these findings to the community.